Optical information recording medium and method for producing the same

Abstract

An optical information recording medium includes a first substrate; at least a first dielectric layer and a recording layer for signal recording provided on a surface of the first substrate; and a second substrate. The first substrate and the second substrate are assembled together in the state of being warped in planar symmetry and flattened. The first dielectric layer and the recording layer is interposed between the first substrate and the second substrate.

What is claimed is:  
     
       1. An optical information recording medium, comprising: 
       a first substrate;  
       at least a first dielectric layer and a recording layer for signal recording provided on a surface of the first substrate; and  
       a second substrate,  
       wherein the first substrate and the second substrate are assembled together in the state of being warped in planar symmetry with respect to each other and flattened, the first dielectric layer and the recording layer being interposed between the first substrate and the second substrate.  
     
     
       2. An optical information recording medium according to claim  1 , further comprising a thin layer provided on a surface of the second substrate, the surface being opposed to the first substrate. 
     
     
       3. An optical information recording medium according to claim  2 , wherein the thin layer includes a second dielectric layer. 
     
     
       4. An optical information recording medium according to claim  2 , wherein the thin layer includes a second dielectric layer formed of an identical material as that of the first dielectric layer provided on the first substrate. 
     
     
       5. An optical information recording medium according to claim  3 , wherein the thin layer includes a metal layer. 
     
     
       6. An optical information recording medium according to claim  2 , wherein the thin layer has such a thickness to warp the second substrate to substantially an equal degree with the first substrate. 
     
     
       7. An optical information recording medium according to claim  1 , further comprising a resin layer formed of a resin provided on a surface of the second substrate which shrinks when being cured, the resin layer being provided on the surface not facing the first substrate. 
     
     
       8. An optical information recording medium according to claim  7 , wherein the resin layer is formed of a UV curable resin. 
     
     
       9. An optical information recording medium according to claim  7 , wherein the resin layer is transparent with respect to UV light. 
     
     
       10. An optical information recording medium according to claim  7 , wherein the resin layer is non-transparent with respect to visible light. 
     
     
       11. An optical information recording medium according to claim  10 , wherein the resin layer has graphics thereon. 
     
     
       12. An optical information recording medium according to claim  1 , wherein the second substrate is warped while being formed. 
     
     
       13. An optical information recording medium according to claim  12 , wherein the second substrate is formed by an injection method. 
     
     
       14. An optical information recording medium according to claim  1 , wherein at least one of the first substrate and the second substrate has a thickness of about 0.8 mm or less. 
     
     
       15. A method for producing an optical information recording medium, comprising the steps of: 
       forming at least a first dielectric layer and a recording layer for signal recording on a surface of a first substrate;  
       warping a second substrate; and  
       assembling the first substrate, which is warped, and the second substrate in planar symmetry with respect to each other, and flattening an assembly of the first substrate and the second substrate.  
     
     
       16. A method according to claim  15 , wherein the step of warping the second substrate includes the step of forming a thin layer on a surface of the second substrate, the surface being opposed to the first substrate. 
     
     
       17. A method according to claim  16 , wherein the step of forming the thin layer includes the step of forming a second dielectric layer. 
     
     
       18. A method according to claim  16 , wherein the step of forming the thin layer includes the step of forming a second dielectric layer formed of an identical material with that of the first dielectric layer. 
     
     
       19. A Method according to claim  17 , wherein the step of forming the thin layer includes the step of forming a metal layer. 
     
     
       20. A method according to claim  15 , wherein the step of warping the second substrate includes the step of forming a resin layer of a resin which shrinks when being cured on a surface of the second substrate, the resin layer being formed on the surface not facing the first substrate. 
     
     
       21. A method according to claim  20 , wherein the step of forming the resin layer includes the step of forming a UV curable resin layer. 
     
     
       22. A method according to claim  15 , wherein the step of warping the second substrate includes the step of causing a warp to the second substrate while the second substrate is being formed. 
     
     
       23. A method according to claim  22 , wherein the second substrate is formed by an injection method.